Imbalanced MHC class II molecule expression at surface of murine B cell lymphomas

To study the role of class II MHC expression in mouse lymphomagenesis, we examined the cell surface expression of I-A/E antigens on 24 spontaneous or murine leukemia virus (MuLV)-induced mouse B10.A (I-Ak, I-Ek) B cell lymphomas. Two primary B10.A B cell lymphomas were observed with strong I-Ek expression but with only minimal cell surface I-Ak expression. Both tumors are readily transplantable in syngeneic mice, with maintenance of their I-A-, I-E+ phenotype. Strikingly, one I-A-, I-E+ B cell lymphoma contains a (11; 17) translocation with a breakpoint on chromosome 17 that is localized within or very close to the H-2 complex. DNA of both tumors contains normal restriction enzyme fragments of the A alpha and A beta genes. Northern blot analyses indicated that one I-A-, I-E+ tumor strongly expressed A alpha, E alpha, and E beta mRNAs but possessed only a weak expression of A beta mRNA. The other B cell lymphoma showed A beta, E alpha, and E beta mRNA expression but only minimal A alpha mRNA expression. In 11 primary B10.A B cell lymphomas with a normal I-A+, I-E+ phenotype, no imbalances in A alpha/A beta mRNA levels were observed. The implications of these findings for the role of class II MHC expression in mouse B cell lymphoma-genesis are discussed.     

Sarcoidosis and primary biliary cirrhosis

Summary An unusual case of a woman with primary biliary cirrhosis and cutaneous sarcoidosis is described. The factors that allow a specific diagnosis of each condition are presented and the literature pertaining to such complex and unusual cases is presented.This work was supported in part by a grant from the Gastroenterology Medical Research Foundation of Southwestern Pennsylvania.     

General practitioners' evaluation of community psychiatric services: responsiveness to change of the General Practitioner Experiences Questionnaire (GPEQ)

Background  

Instruments have been developed to assess professional views of the quality of care but have rarely been tested for responsiveness to change. The objective of this study was to test the responsiveness of the General Practitioner Experiences Questionnaire (GPEQ) for the measurement of Community Mental Health Centres in Norway.     

N-linked glycan modification on antigen-presenting cells restores an allospecific cytotoxic T cell response

The B6 anti-bm6 allospecific CTL response is strictly dependent on CD4+ cells when using LPS blasts as stimulator cells. Altering the N-linked carbohydrates on stimulator cells by use of the N-linked trimming glycosidase inhibitors 1-deoxymannojirimycin and swainsonine, or by treatment with bacterial neuraminidase, results in a restoration of the B6 anti-bm6 response in the absence of CD4+ cells. The extent of restoration is inversely correlated with the number of sialic acids present on N-linked glycans of stimulator cells.     

Angiolymphoid hyperplasia with eosinophilia: A disease that may be confused with malignancy

Twelve new cases of an unusual, benign vasoproliferative and inflammatory disorder of unknown etiology, angiolymphoid hyperplasia with eosinophilia (ALHE), are described and contrasted clinically and pathologically with those appearing in the literature. Only recently recognized in the United States, the disease is of singular importance because the vascular component may be confused histologically with angiosarcoma, thereby resulting in unwarranted aggressive therapeutic measures. ALHE characteristically affects adults and presents in the head and neck region as either solitary or multiple cutaneous tumors. The lesions are pruritic, frequently bleed after minor trauma, and may be associated with peripheral eosinophilia and regional lymphadenopathy. On rare occasions, the disease may masquerade as a salivary-gland tumor, cause stenosis of the external auditory canal, or present as an osseous lesion of the skull. Extrafacial tumors are uncommon. Excision is the most frequent form of therapy; however, local irradiation, corticosteroids, electrodessication with curettage, and chemotherapy have also had varying degrees of success.     

Distinct chromosomal abnormalities in murine leukemia virus-induced T- and B-cell lymphomas

We performed a cytogenetic study on 16 murine mature B-cell lymphomas and 10 T-cell lymphomas, using G-banding techniques. All tumors, with the exception of 3 spontaneous B-cell tumors, were induced by various slowly transforming murine leukemia viruses (MuLV). Metaphases were obtained from primary (10 B-cell tumors) and first or second transplant generation lymphomas (6 B-cell and 10 T-cell tumors), all of which were well characterized with respect to phenotypic, histologic and genotypic features. In the T-cell tumors we found relatively simple karyotypic abnormalities, including various numerical aberrations, such as trisomy 15, in line with many earlier reports. However, the majority of B-cell tumors showed a great variety of both structural and numerical chromosomal anomalies. Three B-cell lymphomas had an apparently normal karyotype. No single cytogenetic abnormality occurred commonly in the B-cell lymphomas, but some structural abnormalities were found in more than one stemline, in particular, ins (II) (A1; A2) in 3 tumors, and deletions involving the D-region of chromosome 14 in 3 other lymphomas. These cytogenetic results clearly indicate that the pathogenic mechanisms involved in MuLV-induced (long latency) B-cell lymphomagenesis and (short latency) T-cell lymphomagenesis differ considerably.